(19)
(11) EP 1 416 516 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
12.04.2006 Bulletin 2006/15

(43) Date of publication A2:
06.05.2004 Bulletin 2004/19

(21) Application number: 03024707.6

(22) Date of filing: 28.10.2003
(51) International Patent Classification (IPC): 
H01J 61/12(2006.01)
 H01J 9/38(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR
Designated Extension States:
AL LT LV MK

(30) Priority: 01.11.2002 JP 2002319980

(71) Applicant: USHIODENKI KABUSHIKI KAISHA
Chiyoda-ku, Tokyo 100-0004 (JP)

(72) Inventors:
  • Kawaguchi, Masataka
    Himeji-shi Hyogo-ken (JP)
  • Uramoto, Motoko
    Kakogawa-shi Hyogo-ken (JP)
  • Masashi, Dan
    Himeji-shi Hyogo-ken (JP)
  • Horikawa, Yoshihiro
    Himeji-shi Hyogo-ken (JP)

(74) Representative: Tomerius, Isabel et al
Lang & Tomerius, Bavariaring 29
80336 München
80336 München (DE)

   


(54) Discharge lamp and method to produce it


(57) A high lumen maintenance factor even after a long time operation is obtained from a discharge lamp (1) which has a silica glass discharge vessel (10) and a pair of opposed electrodes (14,15) in the discharge vessel (10) and in which the discharge vessel (10) is filled with at least 0.15 mg/mm3 of mercury, a rare gas with argon as the main component, and 2 x 10-4 µmole/mm3 to 7 x 10-3 µmole/mm3 bromine by meeting the following conditions when feeding a direct current of 5 mA between the electrodes (14,15) and a glow discharge is produced:







where a is the emission intensity of the argon with a wavelength of 668 nm, b is the emission intensity of OH with a wavelength of 309 nm, c is the emission intensity of hydrogen (H) with a wavelength of 656 nm, d is the emission intensity of C2 with a wavelength of 517 nm, and e is the emission intensity of CH with a wavelength of 431 nm.







Search report